惯性颗粒所见流场拓扑结构

本文采用直接数值模拟的方法从颗粒所见的流场拓扑结构这一角度探讨了颗粒在不同拓扑结构下速度统计特性.结果表明,不同惯性的颗粒所见流体的速度特性类似,在Top1和Top2结构中,随时间演化而减少,而在Top3和Top4结构中随时间有波浪性的增长;由于颗粒惯性的差异引起的轨道交叉效应不同,颗粒与颗粒所见流体速度的关联随颗粒增大而衰减加剧,在颗粒与流体相之间的能量传递中,不同拓扑结构明显不同,从颗粒加入时能量由颗粒相向流体传递,各拓扑结构的相对强度为Top2>Top4>Top1>Top3,演化到后期能量由流体相向颗粒相传递,相对强度为Top1>Top2>Top3>Top4;st=1.0和st=10.0的颗粒差别在于演化后期Top2和Top3相对强度的转变.

TOPOLOGICAL STRUCTURES SEEN BY INERTIAL PARTICLES

In this paper,the statistics of velocity in different topological structures along inertial particles is studied with direct numerical simulation.As the results show that the fluid velocity statistics along particle trajectories are almost identical with the development of time,the statistics decrease in Topl and Top2 and increase wave-like in Top3 and Top4.The velocity correlation between particles and fluid at a particle point decreases rapidly as the inertia increases because the effect of trajectory-crossing and the energy transform between particles and fluid on different topology is very different.When the particles are released,the energy transforms from particle phase to fluid with the relative magnitude of Top2>Top4>Top1>Top3,as the time developed.the direction of energy transform reversed with the relative magnitude of Top1>Top2>Top3>Top4.the difference between the st=1.0 and st=10.0 particle.is the relative magnitude between Top2 and Top3.